Scottish universities including Edinburgh have come under fire for the low number of students they take from Scotland's poorest households, but how does educational inequality vary across the country? Photograph: Murdo Macleod for the Guardian

Scotland's leading universities, particularly St Andrews, Edinburghand Aberdeen, are facing increasing pressure from Scottish ministersand student leaders over the low number of students from the pooresthouseholds who win undergraduate places.

The question many universities ask is: how many students from the mostdeprived backgrounds get the right grades? And if the number is low,is that their fault?

For the first time, the Scottish government has released detailedstatistics after a freedom of information request by the Guardian onexactly how many fifth year students from the poorest 20% of Scottishhousholds got three or more A grades at Highers – a qualificationroughly equivalent to English A Levels, but taken in one academicyear.

The NUS Scotland data was based only on those students who got threeor more Highers, without looking at their grades – a measure theuniversities regarded as unfairly ambiguous.

But looking at school pupils who achieved three or more As, the answerfor Scotland as a whole is 220 in 2011, or just 2.5% of the 8,872fifth year students who came from these households. In 2007, thenumber was 175, or 2% of the 9,026 fifth years from SIMD20 areas.

You can explore the full 2011 data-set, including figures for every Scottish local authority, in our interactive map.

The Scottish Government has been clear that education in Scotland should be based on the ability to learn, not the ability to pay and we are committed to widening access to Higher Education via the Post 16 Reform Bill, which will be introduced later in the year.

I recently wrote a letter of guidance to the Scottish Funding Council setting out priorities for investment in further and higher education institutions. This move should be seen as part of the return for the continuing high level of investment in Scottish higher education, and should also open up opportunities for hundreds of young people to fulfil their potential, when they may not otherwise have the chance to

These universities argue they are "fishing in a very small pond." Andthat competition intensified even more in June, after Oxforduniversity announced it had extended its support package for poorstudents to Scottish applicants: they would receive £22,000 over threeyears towards living and university costs.

However, Oxford's entry requirements are extremely tough: it needs aminimum of four As and one B at Higher. In 2011, only 50 pupils fromthe poorest areas got five As at one sitting, with another 70 gettingfour As.

The data uses the Scottish index of multiple deprivation (SIMD) whichassesses the relative poverty levels of every postcode in Scotland. Itis divided into five segments of 20% each: the poorest neighbourhoodsare known as SIMD20 postcodes.

The Scottish government data also reveals wide disparities in theperformances of local authorities. Glasgow, which has nearly 2400fifth year pupils from the poorest 20% of households, saw 58 or 2.4%of those pupils get those grades – close to the Scotland-wide averageof 2.5%.

East Dunbartonshire, which like Edinburgh has a strong local economybut fewer areas of deprivation, achieved 8.6%, and in EastRenfrewshire, the council with Scotland's best-performing schools,5.6% of its poorest children achieved three As.

The data tables have excluded precise figures for seven councils whereless than five pupils achieved three or more As for data protectionreasons: those include Aberdeen and Perth & Kinross. Some councils,such as Orkney, Shetland and the Western Isles have relatively lowpopulations and do not have SIMD20 postcodes.

In other councils such as Stirling, the Borders, Moray and Midlothianthere were no state school pupils at all who achieved three As; forthem, the number of pupils from SIMD20 postcodes were quite small.Moray had just 22 poor students staying on until fifth year.

These tables do not include any students at private school: theScottish government no longer holds those figures, so it is possiblethat gifted students from SIMD20 areas on scholarships and bursariesmay be missed.

Edinburgh university, which has an intensive programme called LothiansEqual Access Programme for Schools with the city council to increaseattainment rates in deprived areas, also points out that the SIMD20measure will miss pockets of deprivation and poor households inwealthier postcodes. So there will be students from deprivedbackgrounds not included in this data. (Equally, there will be betteroff students from SIMD20 postcodes who are in the figures.)

Adding that its entrance grades varied greatly across courses anddepartments, Edinburgh university pointed out this statement from theumbrella body Universities Scotland on "widening access":

We need to be careful about putting too much weight on one statistical measure, such as the SIMD, which has a number of serious limitations, and instead allow universities to continue to focus efforts on projects that are known to make a difference to people's lives

It uses additional weighting for students from poorer backgroundswhich can influence the grades they require from an individualapplicant. That will include schools with poor attainment records,children from care or those without university-educated parents, orhad serious disruption to their education, such as illness ordisability.

St Andrews has a similar policy: it will give priority to a studentfrom SIMD20 postcodes or similar backgrounds to Edinburgh over astudent with identical grades from a more privileged background. Itgives places to 25% of applicants from SIMD20 postcodes, compared toan average acceptance rate of 10%.

Data summary

Percentages of pupils achieving three or more As in Scottish Highers, 2011, by income quintile

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